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The major histocompatibility complex (MHC) is a genetic region in jawed vertebrates that contains key genes involved in the immune response. Associations between the MHC and avian malaria infections in wild birds have been observed and mainly explored in the Northern Hemisphere, while a general lack of information remains in the Southern Hemisphere. Here, we investigated the associations between the MHC genes and infections with Plasmodium and Haemoproteus blood parasites along a latitudinal gradient in South America. We sampled 93 rufous-collared sparrows ( Zonotrichia capensis ) individuals from four countries, Colombia, Ecuador, Peru, and Chile, and estimated MHC-I and MHC-II allele diversity. We detected between 1-4 (MHC-I) and 1-6 (MHC-II) amino acidic alleles per individual, with signs of positive selection. We obtained generalized additive mixed models to explore the associations between MHC-I and MHC-II diversity and latitude. We also explored the relationship between infection status and latitude/biome. We found a non-linear association between the MHC-II amino acidic allele diversity and latitude. Individuals from north Chile presented a lower MHC genetic diversity than those from other locations. We also found an association between deserts and xeric shrublands and a lower prevalence of Haemoproteus parasites. Our results support a lower MHC genetic in arid or semi-arid habitats in the region with the lower prevalence of Haemoproteus parasites., Competing Interests: The authors have no conflicts of interest to declare., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)

Ticks are a globally distributed group of hematophagous ectoparasites that parasitize terrestrial vertebrates such as amphibians, reptiles, birds, and mammals. Ticks are vectors and reservoirs of pathogens that play an important role in wildlife and human health. Rickettsia is one of the bacteria transmitted by ticks, which some pathogenic species can cause rickettsiosis, a zoonotic disease that can cause serious harm to humans and animals. More information is necessary on the interactions between ticks and wildlife despite the fifty-seven ticks species already identified in Colombia. The objective of the present study was to determine the associations between ticks parasitizing wildlife and bacteria of the genus Rickettsia in six departments of Colombia. One hundred eighty-five ticks (80 larvae, 78 nymphs, and 27 adults) were collected from 55 wildlife species (amphibians, birds, mammals, and reptiles). Nine tick species were identified, and Rickettsia bellii, Rickettsia felis, 'Candidatus Rickettsia colombianensi' and Rickettsia parkeri were detected. Our results contribute to the current knowledge of tick-associated rickettsiae and the role of wildlife in their transmission dynamics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier GmbH.)

Morphological traits from blood stages have been the gold standard for determining haemosporidian parasite species. However, the status of some taxa and the value of such traits in parasites from reptiles remain contentious. The scarce sampling of these species worsens the situation, and several taxa lack molecular data. A survey was performed in the Magdalena Department in Colombia, where 16 species of reptiles were captured. A peculiar haemosporidian parasite was found in the Turnip-tailed gecko Thecadactylus rapicauda . This haemosporidian does not show malarial pigment in blood stages under light microscopy; thus, it fits the Garnia genus's characters belonging to the Garniidae . However, the phylogenetic analyses using a partial sequence of cytochrome b and the mitochondrial DNA placed it within the Plasmodium clade. Our findings suggest that many putative Garnia species belong to the genus Plasmodium , like the one reported here. This study either shows that visible malarial pigment in blood stages is not a diagnostic trait of the genus Plasmodium or malarial pigment might be present in an undetectable form under a light microscope. In any case, the current taxonomy of haemosporidian parasites in reptiles requires revision. This study highlights the importance of using molecular and morphological traits to address taxonomic questions at the species and genus levels in haemosporidian parasites from reptiles.

Haemosporidian genera Plasmodium , Haemoproteus and Leucocytozoon , responsible for avian malarial infections, are highly diverse and have a wide range of health effects and predictors, depending on the host and its environmental context. Here, we present, for the first time, detailed information on the identity, prevalence and parasitaemia of haemosporidians and other haemoparasites that infect the ash-breasted Sierra finch, Geospizopsis plebejus , in an Andean dry forest. We study the consequences of infection in the host body and health conditions and explore the environmental and intrinsic factors that influence infection status and parasitaemia. We conducted diagnoses by cytochrome b ( cytb ) sequencing and morphological identification, and estimated the levels of parasitaemia based on microscopy. We identified 6 cytb lineages infecting G. plebejus . Two of them were new lineages: Haemoproteus sp. GEPLE01 and GEPLE02. We also detected Haemoproteus sp. ZOCAP08, Haemoproteus sp. AMAVIR01, Plasmodium homopolare BAEBIC02 and Plasmodium cathemerium ZONCAP15. By microscopy, we detected Haemoproteus coatneyi , Haemoproteus erythrogravidus , P. homopolare and other unidentified species of Haemoproteus , Plasmodium , Babesia sp. and 1 microfilaria. We found no evidence of Leucocytozoon . Additionally, we detected several coinfections by sequencing and microscopy. The prevalence of haemosporidian infections was high (87.7%), and the mean parasitaemia was 61.65 infected cells per 10 000 erythrocytes examined. Prevalence and parasitaemia were higher for Haemoproteus than for Plasmodium . Haemoproteus sp. AMAVIR01 showed the highest prevalence (43.1%) and mean parasitaemia (94.39/10 000 erythrocytes) and might be associated with H. coatneyi . Immature individuals showed a lower prevalence than adults, supporting previous findings.

The Podocnemididae family is seriously affected by anthropogenic factors, which is why almost all of their family members are threatened, according to the IUCN red list. The biology and ecology of these species, as well as the hematological and serum chemistry reference intervals that allow clinical action and decision-making conservation programs, are poorly known. Based on this, the objective of this study was to establish the hematological and blood chemistry parameters of the Savannah side-necked turtle ( Podocnemis vogli ) and Yellow-spotted river turtle ( Podocnemis unifilis ) maintained in captivity at the Estación de Biología Tropical Roberto Franco (Villavicencio-Colombia). Forty-nine captive turtles of the species P. vogli (n = 28) and P. unifilis (n = 21) were sampled to determine hematological and serum chemistry parameters. Blood samples were taken from the jugular veins of both male and female turtles across both species. Student's t -test and Mann-Whitney-Wilcoxon tests were used to compare values between the parameters evaluated against genders and sizes. Reference intervals were calculated for the hematological and biochemical values of each species. Some assessed parameters demonstrated significant differences between the males and females of both species. Most of the analyzed parameters exhibited similar reference intervals in both species. In this study, we report values and propose the hematological and serum chemistry reference intervals for P. vogli and P. unifilis , which can be used in the clinical diagnosis of these reptiles and in future research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rodríguez-Almonacid, Fuentes-Rodríguez, González, Moreno-Torres and Matta.)

The Orinoco crocodile ( Crocodylus intermedius , Graves, 1918) is the most threatened crocodilian of South America. There is only scarce information available about the physiology of this neotropical crocodile. This study aimed to propose baseline hematological and biochemistry reference data and intervals and a morphological description of the peripheral blood cells of captive C. intermedius . Blood was collected from 318 clinically healthy individuals maintained in captivity at Villavicencio, Colombia. Eight of these individuals were sampled and resampled, and these data were compared. Reference intervals were proposed for hematological values [packed cell volume (PCV), red blood cell count, white blood cell count, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, hemoglobin, and white blood cell count differential counts] and biochemistries [total solids, alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatine kinase, glucose, albumin, cholesterol, uric acid, creatinine, and lactate] including adults and juveniles, males and females' crocodiles. Blood cell morphology for the species is described. Significant differences between sex and age were observed. The intraindividual analysis concluded differences for total solids ( P ≤ 0.01) and red blood cell counts ( P ≤ 0.01). Some biochemical analytes showed a moderate correlation between them, such as ALT-alkaline phosphatase and ALT-uric acid. We present here novel and baseline data with special importance for the clinical diagnosis, improving the national reintroduction programs from either in situ and ex situ populations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Barajas-Valero, Rodríguez-Almonacid, Rojas-Sereno, Moreno-Torres and Matta.)

Haemogregarines (Adeleorina) have a high prevalence in turtles. Nevertheless, there is only one Hepatozoon species described that infects Testudines so far; it is Hepatozoon fitzsimonsi which infects the African tortoise Kinixys belliana. Colombia harbours a great diversity of chelonians; however, most of them are threatened. It is important to identify and characterize chelonian haemoparasite infections to improve the clinical assessments, treatments and the conservation and reintroduction programs of these animals. To evaluate such infections for the Colombian wood turtle Rhinoclemmys melanosterna, we analysed blood from 70 individuals. By using the morphological characteristics of blood stages as well as molecular information (18S rRNA sequences), here we report a new Hepatozoon species that represents the first report of a hepatozoid species infecting a semi-aquatic continental turtle in the world. Although the isolated lineage clusters within the phylogenetic clades that have morphological species of parasites already determined, their low nodal support makes their position within each group inconclusive. It is important to identify new molecular markers to improve parasite species identification. In-depth research on blood parasites infecting turtles is essential for increasing knowledge that could assess this potential unknown threat, to inform the conservation of turtles and for increasing the state of knowledge on parasites.

The genus Haemocystidium was described in 1904 by Castellani and Willey. However, several studies considered it a synonym of the genera Plasmodium or Haemoproteus . Recently, molecular evidence has shown the existence of a monophyletic group that corresponds to the genus Haemocystidium . Here, we further explore the clade Haemocystidium spp. by studying parasites from Testudines. A total of 193 individuals belonging to six families of Testudines were analyzed. The samples were collected in five localities in Colombia: Casanare, Vichada, Arauca, Antioquia, and Córdoba. From each individual, a blood sample was taken for molecular analysis, and peripheral blood smears were made, which were fixed and subsequently stained with Giemsa. The prevalence of Haemocystidium spp. was 1.55% (n = 3/193); all infected individuals belonged to Podocnemis vogli (Savanna Side-necked turtle) from the department of Vichada. This is the first report of Haemocystidium spp. in Colombia and in this turtle species. The phylogenetic analysis of a mitochondrial c ytb fragment revealed Haemocystidium spp. as a monophyletic group and as a sister taxon of Haemoproteus catharti and the genus Plasmodium . Haemocystidium spp. are difficult to identify by morphology only. As a result, it is possible that some of the taxa, such as Haemocystidium ( Simondia ) pacayae , represent a species complex. The parasite found in our study is morphologically indistinguishable from Haemocystidium ( Simondia ) pacayae reported in Peru. However, the new lineage found in P. vogli shows a genetic distance of 0.02 with Hae. pacayae and 0.04 with Hae. peltocephali . It is proposed that this divergent lineage might be a new species. Nevertheless, additional molecular markers and ecological features could support this hypothesis in the future., Competing Interests: The authors declare that they have no conflict of interest., (© 2019 The Authors.)

Avian communities from South America harbor an extraordinary diversity of Leucocytozoon species (Haemosporida, Leucocytozoidae). Here, of 890 birds sampled, 10 (1.2%) were infected with Leucocytozoon parasites. Among them, two new species were discovered and described. Leucocytozoon grallariae sp. nov. and Leucocytozoon neotropicalis sp. nov. were found in non-migratory highland passeriforms belonging to the Grallaridae and Cotingidae, respectively. They both possess gametocytes in fusiform host cells. However, due to combining microscopic examination and molecular detection, it was revealed that these parasites were present in co-infections with other Leucocytozoon species, which gametocytes develop in roundish host cells, therefore exhibiting two highly distant parasite lineages isolated from the same samples. Remarkably, the lineages obtained by cloning the mtDNA genomes were not captured by the classic nested PCR, which amplifies a short fragment of cytochrome b gene. Phylogenetic analyses revealed that the lineages obtained by the classic nested PCR clustered with parasites possessing gametocytes in roundish host cells, while the lineages obtained by the mtDNA genome PCR protocol were closely related to Leucocytozoon parasites possessing gametocytes in fusiform host cells. These findings suggest problems with the sensitivity of the molecular protocols commonly used to detect Leucocytozoon species. A detailed analysis of the primers used in the classic nested PCR revealed a match with DNA sequences from those parasites that possess gametocytes in roundish host cells (i.e., Leucocytozoon fringillinarum ), while they differ with the orthologous regions in the mtDNA genomes isolated from the samples containing the two new species. Since these are mixed infections, none of the lineages detected in this study can be assigned accurately to the new Leucocytozoon morphospecies that develops in fusiform host cells. However, phylogenetic analyses allowed us to hypothesize their most probable associations. This study highlights the need for developing detection methods to assess the diversity of Leucocytozoon parasites accurately.

The Hoatzin ( Opisthocomus hoazin ) is the only extant member of the order Opisthocomiformes. This unique South American bird lives in the riparian lowland vegetation characteristic of the Amazon and Orinoco basins. Hoatzins nest in communal social units close to water bodies; they are strictly folivores being the only bird with pregastric fermentation in the crop. Because of the complex logistics involved in capturing this bird, there is a knowledge gap on its parasites. This study documents two distant lineages of haemosporidian parasites ( Plasmodium spp.) in a juvenile and two adults sampled in the Cojedes state, Venezuela. Although negative by microscopy, the parasite identification was possible by using molecular methods. We estimated the phylogenetic relationships on the parasite cytochrome b ( cytb, 480 bp) gene and the mitochondrial DNA. We found one of the parasites lineages in two individuals (nestling and adult), and the corresponding fragment of cytb was identical to a one found in Wood Stork ( Mycteria americana ) from Brazil. The other lineage, found in an adult, has an identity of 469 out of 478 bp (98%) with Plasmodium sp. GAL-2012 (isolate THAMB08) from Brazil. Although a morphological description of these parasites was not possible, this is the first molecular study focusing on Hoatzin haemosporidian parasites and the first documentation of Plasmodium infections in the Hoatzin from Venezuela. Furthermore, we reported microfilaria in two adults as well as hematological parameters for six individuals. Information on hematological parameters could contribute to establishing the necessary baseline to detect underlying conditions, such as infections, in this bird species., Competing Interests: The authors declare there are no competing interests.

Members of the order Haemosporida are protist parasites that infect mammals, reptiles and birds. This group includes the causal agents of malaria, Plasmodium parasites, the genera Leucocytozoon and Fallisia, as well as the species rich genus Haemoproteus with its two subgenera Haemoproteus and Parahaemoproteus. Some species of Haemoproteus cause severe disease in avian hosts, and these parasites display high levels of diversity worldwide. This diversity emphasizes the need for accurate evolutionary information. Most molecular studies of wildlife haemosporidians use a bar coding approach by sequencing a fragment of the mitochondrial cytochrome b gene. This method is efficient at differentiating parasite lineages but insufficient for accurate phylogenetic inferences in highly diverse taxa such as haemosporidians. Recent studies have utilized multiple mitochondrial genes (cyt b, cox1 and cox3), sometimes combined with a few apicoplast and nuclear genes. These studies have been highly successful with one notable exception: the evolutionary relationships of the genus Haemoproteus remain unresolved. Here we describe the transcriptome of Haemoproteus columbae and investigate its phylogenetic position recovered from a multi-gene dataset (600 genes). This genomic approach restricts the taxon sampling to 18 species of apicomplexan parasites. We employed Bayesian inference and maximum likelihood methods of phylogenetic analyses and found H. columbae and a representative from the subgenus Parahaemoproteus to be sister taxa. This result strengthens the hypothesis of genus Haemoproteus being monophyletic; however, resolving this question will require sequences of orthologs from, in particular, representatives of Leucocytozoon species.

Haemosporidians are a diverse group of vector-borne parasitic protozoa that includes the agents of human malaria; however, most of the described species are found in birds and reptiles. Although our understanding of these parasites' diversity has expanded by analyses of their mitochondrial genes, there is limited information on these genes' evolutionary rates. Here, 114 mitochondrial genomes (mtDNA) were studied from species belonging to four genera: Leucocytozoon, Haemoproteus, Hepatocystis, and Plasmodium. Contrary to previous assertions, the mtDNA is phylogenetically informative. The inferred phylogeny showed that, like the genus Plasmodium, the Leucocytozoon and Haemoproteus genera are not monophyletic groups. Although sensitive to the assumptions of the molecular dating method used, the estimated times indicate that the diversification of the avian haemosporidian subgenera/genera took place after the Cretaceous-Paleogene boundary following the radiation of modern birds. Furthermore, parasite clade differences in mtDNA substitution rates and strength of negative selection were detected. These differences may affect the biological interpretation of mtDNA gene lineages used as a proxy to species in ecological and parasitological investigations. Given that the mitochondria are critically important in the parasite life cycle stages that take place in the vector and that the transmission of parasites belonging to particular clades has been linked to specific insect families/subfamilies, this study suggests that differences in vectors have affected the mode of evolution of haemosporidian mtDNA genes. The observed patterns also suggest that the radiation of haemosporidian parasites may be the result of community-level evolutionary processes between their vertebrate and invertebrate hosts., (© The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)

Black flies (Diptera: Simuliidae) are distributed throughout the world, with more than 2200 formally described species. The family is renowned for its high frequency of cryptic species, offering an opportunity for integrative taxonomy, based on morphological, chromosomal, and molecular approaches. The biodiversity within Simulium (Psilopelmia) ignescens and S. (Psilopelmia) tunja in Colombia was estimated from the larval stage; 10 morphoforms were recognized based on 7 structural characters. This remarkable morphological variation was evaluated through 23 markers on the polytene chromosomes. We established 1 new cytoform in each nominal species. The congruence of the morphological and chromosomal assignments was evaluated using the mitochondrial marker Cytochrome Oxidase subunit I (COI) for each morphoform. The molecular data supported the chromosomal recognition of cytoforms (i.e., cryptic species). We also established the suitability of the COI marker for linking the pupal stage with each cytoform. Our results reveal the presence of hidden biodiversity in S. ignescens and S. tunja and demonstrate the power of polytene chromosomes as a tool for evaluating simuliid diversity, while illustrating the importance of integrated analyses in modern taxonomy., (© The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The high avian biodiversity present in the Neotropical region offers a great opportunity to explore the ecology of host-parasite relationships. We present a survey of avian haemoparasites in a megadiverse country and explore how parasite prevalences are related to physical and ecological host characteristics. Using light microscopy, we documented the presence of haemoparasites in over 2000 individuals belonging to 246 species of wild birds, from nine localities and several ecosystems of Colombia. We analysed the prevalence of six avian haemoparasite taxa in relation to elevation and the following host traits: nest height, nest type, foraging strata, primary diet, sociality, migratory behaviour, and participation in mixed species flocks. Our analyses indicate significant associations between both mixed species flocks and nest height and Haemoproteus and Leucocytozoon prevalence. The prevalence of Leucocytozoon increased with elevation, whereas the prevalence of Trypanosoma and microfilariae decreased. Plasmodium and Haemoproteus prevalence did not vary significantly with elevation; in fact, both parasites were found up to 3300 m above sea level. The distribution of parasite prevalence across the phylogeny of bird species included in this study showed little host phylogenetic signal indicating that infection rates in this system are evolutionarily labile. Vector distribution as well as the biology of transmission and the maintenance of populations of avian haemoparasites deserve more detailed study in this system.

This study reports a broadening of the altitudinal range and a new host for Plasmodium (Haemamoeba) lutzi in Colombia. The study was conducted in the city of Bogotá, located in the Eastern Cordillera of Colombia at 2,560 m asl (meters above sea level) with an average annual temperature of 15 C. In total, 156 specimens of birds belonging to 25 species and 14 families were captured using mist nets. The blood samples were collected through venipuncture and analyzed by light microscopy. Plasmodium (H.) lutzi was only found in 2 individuals of Turdus fuscater (Great Thrush). This parasite has previously been reported in Aramides cajaneus (before: Aramides cajanea) (Grey-Necked Wood Rail), a bird found in the lowlands of Brazil, Venezuela, and Colombia. This finding provides evidence for a broad host range for P. lutzi that include 2 different orders, Gruiformes and Passeriformes, and also altitudinal expansion of its distribution. The blood stages were compared with the parasite's original descriptions, and the sequence of the parasite's mitochondrial genome (mtDNA) confirms that P. lutzi is a sister taxa of Plasmodium relictum, as previously proposed.

Leucocytozoon spp. infections have been rarely studied in Neotropical countries. The apparently low prevalence of these parasites compared to the Nearctic regions suggests the absence of competent vectors; however, a 21.3% overall prevalence has recently been reported in non-migratory birds from the páramo region of Chingaza National Natural Park (NNP), where Turdus fuscater (Great Thrush) is the species most frequently infected by these parasites. The present study provides the descriptions of the Leucocytozoon spp. detected in Great Thrushes trapped in Chingaza NNP. The parasites were confirmed by microscopic examination and PCR of blood, histopathology was also done. Leucocytozoon dubreuili and L. fringillinarum gametocytes were observed in blood smears. The corresponding cytochrome b (cyt b) lineages obtained of L. fringillinarum were closely related to lineages previously found in individuals infecting turdiid species sampled elsewhere. This is one of the few reports analyzing Leucocytozoon spp. infections in resident birds from a Neotropical country.

The antigenic profile and infectivity were compared between 3 recent Leishmania (Viannia) isolates from the Amazonian region (Instituto Nacional de Pesquisas da Amazonia [INPA] strains) and 3 World Health Organization (WHO) reference species (Leishmania guyanensis, Leishmania braziliensis, and Leishmania naiffi). Differences were observed in the peak and extent of promastigote growth. The WHO reference strains exhibited significantly higher exponential growth as promastigotes than INPA strains. In the immunoblot analyses, the INPA strains revealed several specific peptide fragments, as well as the greatest recognition frequencies by sera from Leishmania sp.-infected patients; among the latter, antigens derived from L. naiffi were the most frequently recognized. In vitro infection was carried out using mice peritoneal macrophages; all strains were able to enter the macrophages, but only L. amazonensis was able to reproduce. A striking observation was that L. naiffi exhibited the longest survival time inside the macrophages. Our data strongly suggest the application of recently isolated parasites as sources of antigen for diagnosis procedures. Moreover, L. naiffi species possesses several characteristics relevant for its use as a source of novel antigens to be explored in the design of diagnostic tools and vaccines.

Cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis (CL-Lguy) is endemic in the Brazilian Amazon, differing from L. braziliensis infection in clinical, diagnostic, and therapeutic aspects. T-cell reactivity to leishmanial antigens possibly involved in the pathogenesis of CL-Lguy was studied herein. Variable lymphoproliferative responses (LPRs) to Leishmania antigens were found among the 23 studied patients, and 50% of them showed low or no response to these antigens. Active disease was associated with an enrichment of leishmanial-reactive T lymphocytes, mainly TCD4(+). High and low interferon (IFN)-gamma producers were observed. TNF-alpha, interleukin (IL)-10, and IL-5 were consistently detected. CL-Lguy displayed low antibody response in comparison to L. braziliensis patients. CL caused by L. braziliensis presented positive LPRs and higher IFN-gamma production but undetectable IL-5. L. guyanensis seems to induce a down-regulation of the immune system compared with L. braziliensis. This finding could explain some aspects of clinical presentation of CL-Lguy, such as high tissue parasite burden and frequent resistance to therapy.